Topic: Question about drilled or RC valve covers

[jaguar]

I picked up two valve covers and had a question about them.
Each one has different sized bolts.  Was wondering if that made a difference.
Is bigger better?

[Retro Rocket]

Although i would use the one with slightly bigger bolts i don't think it would make any difference, its not meant to be a tight fit, just snugged down to offer the cam towers some support...  Want to sell one..?

[jaguar]

One is promised to a friend.
Was trying to see if they would both work the same and why the difference in thread size.

There should be one or two left in the "massive inventory" for sale thread

[Jim F]

I used 1/4-20 Alan heads on mine but it shouldn't
Make any differance

[johno]

If anyone is interested this is the template ( metric) I used on my cam cover.   the specs use the two dowels as the reference point, just need to use verniers and ruler to find the right spot on top of the cam cover.

[johno]

Just mark out the specs

[johno]

Drill eighth hole on each end of cover, then put cover over head and rocker bearings,  touch drill through hole to bearing then lift the cover and check the hole is in correct spot on the bearing  ie the centre of the casting circle.   if good drill rest, if not adjust the template 1 or 2mm accordingly. then drill the rest of the eighth holes.

[johno]

For those worried about drilling the pilot holes in the wrong spot dont worry I did and its not a problem ( it was winter time and a combo of several XO  brandies and rushing)

Then buy a length of 20mm aluminium rod and get it parted off in 10mm lengths and drill an eighth hole in the centre.

Take it to a welder and he will grind the top ridges on the cover a little to make a flat area for the 10mm pad to sit on, then line the pad with drill or a rivet so its in correct position and get it welded onto the cover.

grind and tidy up  pad  and drill and tap for 1/4 inch course and put in allan bolt with lock nut.

Something for you blokes in the northern hemishere at this time of the year
ciao johno 

[MCRider]

To JAg's original question, mine has 6mm allens in them. I can't see where it makes a difference, just whatever the machinist had on hand.

I'd try to use metric to keep it pure. And it seems to me a fine thread would be better then course? More feel and thread meat.

When I was installing mine we had a discussion as to tightness and the engine builders here concurred only use minimal torque. I used 5ft lbs. These are finesse items not structural.

IIRC too big and tall might foul the gas tank. Maybe not.

[Jim F]

I used 1/4-20 Alan heads on mine but it shouldn't
Make any difference. I turned mine in until they touched the towers and locked the jam nut down
but the allen heads are not in this picture (DUHH)

[754]

Nice to have a drawing easier to scribe with height guage.
 But, Iwood just set the head with towers up on drill press, center to pads, then lift drill up instsll walve cover and then centre drill ..should be accurate..

[MCRider]

Nice to have a drawing easier to scribe with height guage.
 But, Iwood just set the head with towers up on drill press, center to pads, then lift drill up instsll walve cover and then centre drill ..should be accurate..

That's clever.

[voxonda]

Nice to have a drawing easier to scribe with height guage.
 But, Iwood just set the head with towers up on drill press, center to pads, then lift drill up instsll walve cover and then centre drill ..should be accurate..

That's how I do it too.